6 of the Best Dietary Supplements for a Diabetic Diet—and 3 You Should Avoid

Sari HarrarMar 22

Are your favorite natural remedies for treating diabetes effective, or even safe? Read our guide on the best dietary supplements for a diabetic diet before you head to the vitamin aisle.

Should I take supplements?

From cinnamon and magnesium to herbal formulas claiming to smack down high blood sugar, “diabetes-friendly” supplements are popping up in health food stores and drugstores and in the medicine cabinets of more and more people with diabetes. More than 50 percent of people with diabetes say they’ve used dietary supplements, according to one 2011 study—and at least one in four has given herbal remedies a try.

The big question: Should you?

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“People with diabetes may be looking for something that seems less potent than a medication or something that will treat other health issues beyond blood sugar control, such as high cholesterol,” notes Laura Shane-McWhorter, PharmD, a University of Utah professor of pharmacotherapy and author of The American Diabetes Association Guide to Herbs & Nutritional Supplements: What You Need to Know from Aloe to Zinc. But experts are reluctant to recommend supplements to people with diabetes for two important health reasons. First, there’s virtually no research on long-term safety. Second, no supplement controls blood sugar as effectively as diabetes drugs (in combination with a healthy lifestyle).

“There are no miracle treatments for diabetes,” Shane-McWhorter says. “The most important thing to know if you have diabetes is that no supplement will take care of it for you. Diabetes is a condition that can be well-controlled with a healthy lifestyle plus medication if needed. A supplement can’t replace those.”

And new science is changing the supplement landscape. In consulting the latest research as well as supplement experts for this report on the best-studied and most widely used supplements, we found that some popular pills—chromium, we’re talking about you—aren’t living up to their reputations. Others, such as vitamin D or psyllium, may be more promising. Still others should be avoided because they make false claims (supplements that promote weight loss tend to be a red flag). As recently as January of 2012, the FDA told makers of one weight-loss supplement to stop touting it as a diabetes remedy.

However, used safely, certain supplements might help you step up your blood sugar control a notch or two or help control risk for heart disease, the most common and life-threatening diabetes complication. Here, the supplements you should consider adding to (and dropping from) your diabetes treatment plan. Try these healthy habits to prevent diabetes.

Consider this: Vitamin D

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Is there a link between D and blood sugar control? Getting more than 500 international units (IU) of D daily could cut risk for developing diabetes by 13 percent, Tufts Medical Center researchers report. But benefits haven’t yet been proved for people who already have diabetes, says Oluwaranti Akiyode, PharmD, an associate professor in the department of pharmacy practice at Howard University, who studies the effects of vitamin D in people with diabetes. “Low vitamin D has been associated with poor control in early research, but we don’t know yet if taking more helps,” she notes. “Still, there are good reasons to get enough D, including preventing brittle bones.”

The verdict: A daily supplement is recommended by the Institute of Medicine (600 to 800 IU of D daily) and the National Osteoporosis Foundation (800 to 1,000 IU daily). Since one in three Americans may be low on D, and it’s tough getting enough from food, starting a supplement may be smart. But Akiyode suggests first getting a blood test of your vitamin D levels. If you’re deficient, you may need more than a drugstore tablet to top off your tank. “Your doctor may prescribe a high-dose supplement for a while or just suggest an over-the-counter D supplement from the drugstore. Then have your levels rechecked in a few months.” These science-backed strategies can work to reverse diabetes.

Consider this: Omega-3s

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The good fats found in fish oil capsules (as well as in algal oil, supplements made from algae) and fish like salmon, trout, herring, and sardines have long been touted as heart healthy. That’s important for people with diabetes, who are at high risk for heart disease. Omega-3s may reduce inflammation, decrease off-rhythm heartbeats, and discourage artery clogging. In one review of 18 studies, people with diabetes who took fish oil supplements lowered levels of triglycerides (an unhealthy blood fat) significantly. Watch out for these silent signs that you may have diabetes.

The verdict: The American Heart Association recommends that most people get their omega-3s from two or more weekly servings of fish. If you’re not a fish fan, aim for about 2,200 mg weekly of EPA and DHA (the two types of omega-3s) from supplements. People with heart disease should go for 1,000 mg of EPA and DHA daily from fish or a supplement, the AHA recommends. Don’t take higher doses on your own because these can actually raise fasting blood sugar slightly and bump up levels of artery-clogging LDL cholesterol, Dutch researchers report.

Consider this: Magnesium

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One in four people with diabetes may be low in magnesium. High blood sugar and diuretic drugs (which many with diabetes take for high blood pressure) can make your body excrete too much; low levels may affect your ability to use insulin. However, there’s little evidence that getting more than the recommended amounts has extra blood sugar benefits. And too much magnesium can be harmful.

The verdict: Your doctor should check magnesium levels before you start a supplement. Don’t take extra on your own. “If you have kidney damage, which is fairly common in diabetes, your magnesium levels may already be too high,” Shane-McWhorter says. “Excess magnesium may cause low blood pressure and an irregular heartbeat.” A multivitamin with about 100 mg of magnesium, plus several servings of whole grains and green vegetables, may supply all you need. The recommended dietary allowances for magnesium are 400 mg a day for men ages 19 to 30; 420 mg for men after 30; 310 mg for women ages 19 to 30; 320 mg after age 30. The tolerable upper intake for magnesium in supplement form is 350 mg a day.

Consider this: Psyllium

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Known for improving regularity and lowering cholesterol, psyllium supplements contain soluble fiber that slows the natural rise in blood sugar after a meal. “If you aren’t getting enough fiber from your diet, then adding psyllium could be beneficial,” Shane-McWhorter notes.

The verdict: Aim for about ten grams of soluble fiber a day—the amount in three teaspoons of powdered psyllium. This dose lowered after-meal blood sugar levels 13 points in one University of California–San Diego study. Mix one teaspoon in eight ounces of water, and sip 20 to 30 minutes before each meal. Start with smaller doses and work your way up gradually to avoid digestive system discomfort or gas.

Consider this: Cinnamon

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Its compound hydroxychalcone seems to stimulate insulin receptors on cells, which improves your ability to absorb blood sugar. University of California–Davis researchers who recently reviewed eight cinnamon studies report that about half to one teaspoon a day lowered fasting blood sugar levels an average of nine points in those with diabetes.

The verdict: Cinnamon might be worth a try. Aim for 500 mg of cinnamon extract twice daily in capsule form, or one half to about one teaspoon of ground cinnamon daily. Cinnamon alone may not help you reach a healthy A1C goal of less than 7 percent but could help along with other diabetes medications, says Evan Sisson, PharmD, MHA, CDE, associate professor in the department of pharmacotherapy and outcomes science at Virginia Commonwealth University. Steer clear of cinnamon if you have liver damage.

Consider this: Alpha-Lipoic Acid

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If you’re coping with pain in fingers, toes, or feet due to diabetes-related nerve damage, an antioxidant supplement called alpha-lipoic acid (ALA) might help by making nerves less sensitive to pain. It’s possible that ALA may neutralize elevated levels of cell-damaging free radicals that accompany high blood sugar. Some researchers suggest ALA might slow the development of diabetic neuropathy, but that’s based on lab studies, not on long-term studies in people. It also seems to work better when given intravenously rather than as a pill, according to one Dutch review of four studies.

The verdict: Maybe. “Stabbing, burning pain may respond better than ongoing tingling,” Shane-McWhorter says. “And ALA may help more with early nerve damage than with more advanced problems.” The dose used in studies is 600 mg daily. You can also get small amounts of this compound from spinach, broccoli, tomatoes, peas, brussels sprouts, and rice bran.

Skip this: Fenugreek

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Several small studies suggest that fenugreek, an ancient medicinal herb, may help reduce blood sugar in people with diabetes, according to the National Institutes of Health.

The verdict: If fenugreek helps, benefits are small, and side effects—like gas, diarrhea, and interactions with blood-thinning drugs—may outweigh them. “Most of the benefit comes from its dietary fiber,” Shane-McWhorter says, which you can get from foods like these or psyllium. If you want to try it, stick to using seeds in your diet as opposed to supplements. Grind them to use in tea or to mix into baked goods. These diabetes myths could be sabotaging your health.

Skip this: Chromium

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Thanks to 30 years of studies suggesting it may help control blood sugar, chromium is popular among people with type 2 diabetes. Trouble is, studies show chromium supplements improve blood sugar in those with diabetes living in areas where deficiencies are common. That’s not in the United States, where long-term studies haven’t turned up benefits.

The verdict: Save your money. “Almost everyone can get enough from whole grains, broccoli, green beans, mushrooms, and other produce,” says Constance Brown-Riggs, MSEd, RD, CDE, a national spokesperson for the Academy of Nutrition and Dietetics and the author of The African American Guide to Living Well with Diabetes.

“I don’t routinely recommend a chromium supplement unless there is a known deficiency.” High levels can harm the kidneys and liver and cause mood disturbances. (A safe daily intake is 50 to 200 micrograms.) Also, chromium can interfere with medications, including antacids, beta-blockers, and nonsteroidal anti-inflammatory drugs.

Skip this: Bitter Melon

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A popular fruit in the cuisines of Africa, East Asia, India, and South America, bitter melon is also sold in capsules claiming to maintain healthy blood sugar levels. Despite showing promise in test-tube studies, there is limited evidence for real blood sugar benefits in people, according to the National Institutes of Health’s National Center for Complementary and Alternative Medicine.

The verdict: “It’s fine to eat bitter melon as a food, but as a supplement, it hasn’t delivered the expected benefits and is potentially dangerous,” Shane-McWhorter says. “For example, it may cause gastrointestinal discomfort or allergic reactions.”